I'm currently using the USB port of Arduino uno for its power supply.
can i also put a supply to the adaptor part as a reserve supply incase of brownout?
does it affect the arduino?
If its bad for the arduino, what alternative methods or equipments can i use to supply the arduino incase of brownout?
edit by mod: please don't write titles in upper case
Not clear what you are after.
The USB connector is being used to power something else?
If so, where is the Arduino getting power from?
And now you want to power the Arduino from elsewhere also?
How would you tell there is a brownout?
I don't think the arduino would particularly care, the microcontroller would just reset itself when power was restored.